一 help的直接使用

HELP topics

matlab\general       -  General purpose commands.
matlab\ops           -  Operators and special characters.
matlab\lang          -  Programming language constructs.
matlab\elmat         -  Elementary matrices and matrix manipulation.
matlab\elfun         -  Elementary math functions.
matlab\specfun       -  Specialized math functions.
matlab\matfun        -  Matrix functions - numerical linear algebra.
matlab\datafun       -  Data analysis and Fourier transforms.
matlab\polyfun       -  Interpolation and polynomials.
matlab\funfun        -  Function functions and ODE solvers.
。。。。。。。

二 help+函式（）

>> help elfun
  Elementary math functions.
 
  Trigonometric.
    sin         - Sine.
    sind        - Sine of argument in degrees.
    sinh        - Hyperbolic sine.
    asin        - Inverse sine.
    asind       - Inverse sine, result in degrees.
    asinh       - Inverse hyperbolic sine.
    cos         - Cosine.
    cosd        - Cosine of argument in degrees.
    cosh        - Hyperbolic cosine.
    acos        - Inverse cosine.
    acosd       - Inverse cosine, result in degrees.
    acosh       - Inverse hyperbolic cosine.
    tan         - Tangent.
    tand        - Tangent of argument in degrees.
    tanh        - Hyperbolic tangent.
    atan        - Inverse tangent.
    atand       - Inverse tangent, result in degrees.
    atan2       - Four quadrant inverse tangent.
    atanh       - Inverse hyperbolic tangent.
    sec         - Secant.
    secd        - Secant of argument in degrees.
    sech        - Hyperbolic secant.
    asec        - Inverse secant.
    asecd       - Inverse secant, result in degrees.
    asech       - Inverse hyperbolic secant.
    csc         - Cosecant.
    cscd        - Cosecant of argument in degrees.
    csch        - Hyperbolic cosecant.
    acsc        - Inverse cosecant.
    acscd       - Inverse cosecant, result in degrees.
    acsch       - Inverse hyperbolic cosecant.
    cot         - Cotangent.
    cotd        - Cotangent of argument in degrees.
    coth        - Hyperbolic cotangent.
    acot        - Inverse cotangent.
    acotd       - Inverse cotangent, result in degrees.
    acoth       - Inverse hyperbolic cotangent.
 
  Exponential.
    exp         - Exponential.
    expm1       - Compute exp(x)-1 accurately.
    log         - Natural logarithm.
    log1p       - Compute log(1+x) accurately.
    log10       - Common (base 10) logarithm.
    log2        - Base 2 logarithm and dissect floating point number.
    pow2        - Base 2 power and scale floating point number.
    realpow     - Power that will error out on complex result.
    reallog     - Natural logarithm of real number.
    realsqrt    - Square root of number greater than or equal to zero.
    sqrt        - Square root.
    nthroot     - Real n-th root of real numbers.
    nextpow2    - Next higher power of 2.
 
  Complex.
    abs         - Absolute value.
    angle       - Phase angle.
    complex     - Construct complex data from real and imaginary parts.
    conj        - Complex conjugate.
    imag        - Complex imaginary part.
    real        - Complex real part.
    unwrap      - Unwrap phase angle.
    isreal      - True for real array.
    cplxpair    - Sort numbers into complex conjugate pairs.
 
  Rounding and remainder.
    fix         - Round towards zero.
    floor       - Round towards minus infinity.
    ceil        - Round towards plus infinity.
    round       - Round towards nearest integer.
    mod         - Modulus (signed remainder after division).
    rem         - Remainder after division.
    sign        - Signum.

 SIN    Sine.
    SIN(X) is the sine of the elements of X.
 
    See also asin, sind.

    Overloaded functions or methods (ones with the same name in other directories)
       help sym/sin.m

    Reference page in Help browser
       doc sin

 三當用戶不知確切的函式名時，可以使用lookfor,用來進行關鍵字搜尋

四 另外一些常用的

  exist//變數或函式檢驗函式

 what //目錄中檔案列表

  whos//記憶體變數詳細列表

  dir //當前路徑中檔案及資料夾列表